This project involves the development of mammalian lymphoid culture systems to test for the mutagenicity of environmental agents. Compounds which are known mutagens, such as alkylating agents, and frameshift mutagens, will be tested in human and lymphoid cell lines for the induction of mutations at the hypoxanthine-quanine phosphoribosyl transferase and the argininosuccinic acid synthetase loci, and in murine lymphoid cells for the induction of altered immunoglobulin. The induction of chromosomal breakage in these cell lines will be studied using the G and H banding techniques. In addition, the research will utilize bacterial test systems to determine the relationship between mutagenicity in simpler organisms and in more complex, differentiated mammalian cells.